Snap switch mechanisms



March 20, 1956 R. HAPPE ETAL 2,739,198

SNAP SWITCH MECHANISMS Filed Feb. 14. 1951 2,759,198 SNAP SWITCH MECHANISMS keyzuoldHappe, l Pittstowm and Harry B. Fuge, Somer- 'fvlll,

Y py; Elizabeth, N. J., a corporation of New Jersey Application February 14, 1951, Serial No. 210,956 9,(1lain1s. (C'l. 20o-.67)

'Ihis invention relates generally to snap switches and more particularly to' improved'mechanisms for provid ingthefsnap action therefor. "One object of the present invention is to provide an electric switch lhaving improved means for effecting, simultaneously, the quick make and break of two separate electrical contact pairs.

Another objectV of this invention is to provide a novel form of snap switch construction in which an operator shaft passes completelyI through an aperture in a contact-actuator cam 'and forms a bearing :axis therefor;

A still further object of this invention is to provide an improved snap switch comprising a minimum 'number of operating elements positioned within an insulated casing, and a single operative connection extending through said casing. These objects have been attained by providing two re' silienfeontact arms, each normally 'biased towards an openi'po'sition with respect to'a corresponding stationary contact arm, an insulated cam common to said contacts and arranged for positively and simultaneously moving each'ofsaid resilient contact arms to a closed position with respect to'its corresponding stationary contact arm, and means for imparting a snap action to 'said insulating cam.

These and other advantages and features of the in vention will appear from the subjoined detailed descrip# tion of a specific embodiment therefor illustrated in 'the accompanying drawings, of which:

Fig. 1""i's aifopiplan'view ofthe interior of one-half of the switch with the cover removed and in the open position.- v g. 2 p a view similar` to Fig. l except that a Contactactuating amis shown in section in 'the fclosedi position fthqe switch... ""Fig.'3 is'"`a longitudinal section, partly in elevation, taken on the `lii`1e3"-"3 of Fig'fi andincludes theI cover.

Fig. 4 is a transverse section, partly -in elevation, taken on the. line 4f@ of Eisl- Fig- 5, 'iS s detailed, Section taken on the line of Eia3- t Fig. 6 is a detailed section taken on the line 6 6 of Fig. 3.

Referring to the reference characters in the drawings, numerals 10 and 11 represent two hollow associated shells which, when placed together, as shownV in Fig. 3, form a complete enclosing casing for a switch mechanism, Ithe said shells being formed of a dielectric insulating material, preferably a thermosetting plastic.

The shell 10 is formed with a recess 12 having symmetrical walls of such configuration as to provide insulated seats for a pair of identical spring contacts 13--13, which are reversely bent to provide suiiicient exibility. At one end 14 of each of said contacts 13-13, is secured, as by soldering, a conductor 15 of a conventional line cord 16 which passes through an apertured portion 17 of the casing for external connection to a source of supply of electrical energy. The opposite end 18 of each 2,739,198 Patented Mar. 20, 1956 ICC 2 contact is reversely vbent to -form ythe contacting portion which is adapted to make selective electrical contact with one of the stationary spring contacts 19-19.

The stationary contacts -19-19 are connected to pin terminals 20-20 for engagement with the terminals of a lamp bulb which may be received within a socket por; tion 43, which construction is similar to that shown, for example, in the U. S. Patent No. 2,148,875, February 28, 1939.

` -It will be observed that the spring contacts 13-13 and 19-1-9 are arranged symmetrically in pairs about a longis t'udinal center line 3 3, on which line is located a transverse bore 21 in the shell 10. An operator shaft 22 carrying a crank`23 and a pin 24 at ythe interior end extends through said bore 21 and is formed at the exterior end with a square-shaped portion 25 to which a knob 26 is secured by means of a screw 27 passing through said knob 26 and threaded into said shaft.

The shaft 22 forms a bearing axis for a rotatable cam 28y of insulating materia-l and positioned between and in contact with the movable spring contacts 13-13. The cam 28 is formed with a portion 29 of general diamond shape and has a portion formed with a crank 30 and pin 31.

As seen best in Figs. Zand 3, the diamond-shaped por tion'29 is seated in a recess 32 in the interior wall of' the shell 10, which recess has abutment walls 3 3 and 34 which serve as stops for the respective sides 35 and 36 of the diamond-shaped portion of the cam 28 to limit the'vrotation of said cam :to approximately 90 degrees. In the position of the cam, as'shown in Figs. l and 5, the movable contacts 13-13 are out of engagement with the stationary contacts 19-19, but, in the other limited position of the cam, the diamond-shaped portion 29 is positioned with itsv` long axis set crosswise of the space between the movable contacts 13-13 so that they are urged into engagement with the stationary contacts`19- 19', as shown' in'Fi'g. 2, thus completing an electrical circuit from the source of supply to the pins 20-20.

The knob 26 is formed, as shown best in Figs. 3 and 6, with a'rfadial lrib 37 which extends within a recess 38 in the exterior wall of the shell 10, which recess is formed withradiail abutment walls 44 and 45 which serve as stops for said rib to limit the rotation of the knob and hence the shaft 22, the crank 23 and the pin 24, to approximately de`grees; A dished washer 3,9, -free on the shaft 22,- in Ithe; recess 38 between the knob 26 andthe shell 19; takes up any endplay in the shaft assem- Ibly. The screw 27 is seated in a c ounterbore portion 41 of' the knob 26 and is covered by an insulated plug 42 to prevent the possibilityof bodily contact with any 'conducting element communicating with the interior and possibly live parts of the switch.

As 'shown in Figs. l and 3, it will be seen'that the cranks 25 and 30 arev positioned in opposed relation and the pins 24"and 31 are resiliently connected together by means of an over-center spring 40 which establishes two stable positions for each crank on opposite sides of the center line, which positions correspond respectively to a switch-open and a switch-closed condition. Any intermediate position is unstable and cannot be maintained by any manipulation of the knob 26.

In operation, when the knob 26 is turned, the pin 24 pulls on the over-center spring 40 and shifts its line of action to the other side of the axis of rotation of the cam 29, thus instantly reversing the torque on said cam to snap it to its other stable position, thereby opening or closing the switch contacts 13 and 19 as the case may be. It will be noted that, during the operation of the switch, the two crank-s 23 and 30 rotate in opposite directions.

The simple and very compact structural arrangement of the switch is, according to the invention, brought about assunse 3 primarily by the coaxial arrangement between the cam 29 and the shaft 22, in which the shaft passes completely through the cam and forms a bearing axis therefor.

Having thus set forth the nature of the invention, what we claim herein is:

1. In an electric switch, an insulated ca-sing, a stationary contact element and a movable contact element positioned in said casing and mutually biased to a noncontacting position, a rotatable insulated cam positioned in operative relation to said movable contact element for effecting closure of said contact elements, a shaft journaled solely in one wall of said casing and extending through said cam to form a bearing axis therefor, a rst crank formed on said cam, a second crank secured to one end of said shaft, said cranks being mounted in generally opposed relation for limited rotation and being connected by an overcenter spring to establish two stable positions for said cam, and a knob secured to said shaft externally of said casing for rotating said second crank to impart snap-action movement to said cam.

2. In an electric switch, an insulated casing, two movable spring contacts and two corresponding stationary spring contacts positioned within said casing and mutually biased to a non-contacting position, a rotatable insulated cam formed with an apertured portion and positioned between and in operative relation to said movable spring contacts for effecting simultaneous closure of each movable contact with its corresponding stationary contact, a shaft journaled solely in one wall of said casing and extending through said apertured portion to form a bearing axis for said cam, a first crank formed on said cam, a second crank secured to one end of said shaft, said cranks being mounted in generally opposed relation for limited rotation, an over-center spring interconnecting said cranks to establish a stable position for said cam at each limit of its rotation, and means external of said casing for rotating said second crank to impart tosaid cam a snap action movement into a selected one of its limited stable positions.

3.V In an electric switch having an insulated casing and stationary and movable contacts enclosed therewithin, means for actuating said movable contact-s into andout of circuit-making position with said stationary contacts, comprising a rotatable cam positioned within said casing in operative relation to said movable contacts, a shaft journaled solely in one wall of said casing and forming a bearing axis for said cam, a first crank formed on said cam, a second crank securedk to said shaft adjacent and opposed to said first crank, a spring for interconnecting said cranks, an external knob secured to said shaft, and individual means for limiting the angular rotation of each of said cam and said shaft.

4. Apparatus according to claim 3, in which the means for limiting the rotation of the cam comprises an internal recess formed in said casing to provide a seat for said cam, and abutment walls within said recess for engaging a selected surface of said cam in each of its limited positions. y f

5. Apparatus according to claim 3, in which the means for limiting the rotation of the Vshaft comprises a radial rib formed on said external knob, and a recess formed with radial walls in the outer surface of said casing for receiving said rib, said rib engaging the radial walls of said recess in the limited positions of said shaft.

6. in an electric switch, an insulated casing, a shaft journaled for rotation solely in one wall of said casing, an insulated actuator cam apertured to receive said shaft as a bearing axis therefor, said shaft carrying at one end a knob and at the other end a crank, a second crank formed on said'cam and positioned in opposed relation to said first crank, and a spring interconnecting said cranks.

7. In an electric switch, an insulated casing, a pair of stationary contact arms and a pair of spaced-apart resilient Contact arms positioned within said casing and normally biased out of contact with said stationary contact arms, a cam mounted for rotation between and in contact with said spaced-apart resilient contact arms for displacing them into engagement with said stationary contact arms, shaft means journaled solely in one Wall of said casing and forming a bearing axis for said cam, a crank carried by said shaft, a second crank formed on said cam and a spring interconnecting said cranks.

8. In an electric switch, an insulated casing, a crank shaft journaled solely in one wall of said casing, a crank secured thereto, an insulated rotatable cam loosely mounted on said crank shaft, a circuit-closing element operated by said cam, a yieldable connection between said cam and said crank, whereby movement of said crank past a given point will impart movement in a rotary direction to said Y cam opposite to the movement of said crank to operate said circuit-closing element.

9. In an electric switch, an insulated casing, switch contact elements enclosed Within said casing, an apertured portion formed in said casing, a shaft extending through said apertured portion which forms the sole bearing therefor, a knob secured to said shaft externally of said casing, a rotatable cam freely mounted on said shaft internally of said casing and in operative relation to said switch contact elements, a crank secured to said shaft adjacent said cam, a second crank formed on said cam, said cranks being positioned in generally opposed relation and limited in their rotation, and an overcenter spring interconnecting said cranks to establish two limited stable positions for each crank.

References Cited in the tile of this patent UNITED STATES PATENTS v719,265 Seymour Jan. 27, 1903 1,455,960 Maage May 22, 1923 2,059,712 Schellenger Nov. 3, 1936 2,447,871 Riche Aug. 24, 1948 2,626,334 Koenig Ian. 2,0, 1953 FOREGN PATENTS 254,776 Great Britain July 1, 1926 299,041 Italy July 21, 1932 478,801 Great Britain Jan. 25, 1938 

